High mount water pump body/timing cover???

I'm noting from the photos that xMOPARx posted that the marine engine uses a divorced water pump (not plumbed through a front cover). Besides supplying the engine internals, it also puts coolant through the exhaust manifolds. (The funny looking air filter is also a spark arrestor. The marine carb vents differently from the non-marine carbs.)

My experience with industrial engines is that they weren't any different in external appearance from the automotive counterpart. Some have had oil bath air filters, but those were available on cars, too. What I haven't seen on a marine or industrial engine are the fittings for supplying coolant to a heater.

A photo or two of your engine might help shed some light on its origins. Besides a 3/4 view of the entire engine, some close-ups of the water pump area, and any numbers cast into the side of the block would be helpful.